1. Field of the Invention
The present invention relates to a method for controlling a vehicle having a hybrid drive, in which during driving operation an internal combustion engine and a second drive unit contribute individually or jointly to the drive torque of the vehicle.
2. Description of Related Art
Vehicles having a hybrid drive structure, as described in published German patent application document DE 10 2005 051 002 A1, have an internal combustion engine and a second drive unit, which may be an electric motor or a hydraulic drive motor, for example. Novel constraints with regard to the load requirements on the internal combustion engine result in such hybrid drives.
Thus, the drive torque may be applied by both drive units during driving operation. Provided that the quantity of stored energy and the power of the second drive unit are sufficient, the vehicle is driven without the internal combustion engine. In other driving situations, this power which is applied by the second drive unit is generated by the internal combustion engine by delivering a higher load to the drive train. Thus, during hybrid operation the internal combustion engine operates at a higher load level than in a conventional vehicle. When the internal combustion engine is controlled in the same way as for a conventional vehicle, high pollutant emissions result in the event of sudden high load changes, since the quantity of air supplied is not sufficient to oxidize the fuel.